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ADAS,
High Mowthorpe. April, 24th, 25th
26th. 2003.
a)
Docks and Spear thistle in Red Clover seed crop.
b)
Docks in permanent pasture. Organic & Countryside
Stewardship.
Crop:
Red Clover grown for harvesting as seed and silage (Sown
Spring 2002)
Problem:
Mainly Spear Thistle, but also Docks, Sow & Creeping
Thistle.
Area:
31 Acres / 12.5 Hectares (Stone-chair field, see drawing).
Conditions:
Wold land, shallow, dry, stony on brows. Deeper in dip
valleys and flats.
Management:
After a Spring 2002 sowing, the crop had been Autumn grazed
by set-stocked cattle. This had opened up the ground along
the fence-lines (esp. the roadside). The weed problems
were also increased by feed vehicle tracks, seed take-up
failure on stony areas, and two field-length drill breadths
(where the seed ran out).
Density
of weeds : Variable, from low in well
established clover crop (0 to 2 per 25 sq. metres), to
very high in the unsown & exposed areas (up
to 50 or more per 25 sq. metres).
Causes:
Docks were mostly found alongside the boundary, seeded
by established plants in the roadside verge or fence lines.
Scotch thistle probably came from the seed-bank (along
with Sow thistle). Creeping thistle was found in one damp
field corner, growing from the established rhizome, broken
into new sections by cultivations. The worst problems
were related to small areas of crop failure or the cattle
grazing along the boundary fences.
Clearing
the weeds:
Day
1. It took five men 7 hrs to remove the new docks &
scotch thistle from a 5 metre strip that ran alongside
the road (stony & thin). On the other hand, it took
one man only 1.5 hours to remove old docks in the roadside
verge, which were the source of that problem. (Day total
= 37 man-hours)
Day
2. Five men walked 90 % of the field and removed Scotch
thistle rosettes & about 50 dock plants. It rained
(1st for two months) in the afternoon. Approx.
30% of the worst weed Spear thistle infestation in exposed
breadths (to the West), was tackled. 35 man hrs were spent
removing rosettes that covered the ground.
Day
3. Four men took five hours to clear one and half field-length
drill bredes, carpeted with Scotch thistle, with a few
docks along the Western fence line. They also picked up
the dock piles from earlier work & put them in a pile
for collection. They chisel-hoed a small but intense bed
of creeping thistle near the entrance (10 minutes). (Day
total = 20 man hours)
Costs:
Wages
@ £7.14p per hour of lifting: £656.
Travel
& materials cost. Travel & tools: £.70.
Total:
£850. (or £27 per acre ).
Assessment:
an estimated 70% of weeding costs would have been avoided
by crop cover. During sowing, the seed drill seemed to have
run empty for two field length breadths, and there was no
evidence of follow-up repairs on the stony ground. (This
was not noticed during an inspection of the field with Derek
Knight).Cattle were set-stocked rather than strip grazed.
There were vehicle tracks through the crop (for feed delivery
?), and the fence-line docks had not been left to mature.
Too much time was spent weeding in areas where the crop
had failed, and the dry /stony conditions made this work
very difficult. Some of this work could have been tackled
in Autumn.2002.
More
work at A.D.A.S. High Mowthorpe. 29th &
30th April 2003
Permanent
grassland in valley bottom & fenced countryside stewardship
banks. (Organic)
Problems:
a) Docks in valley bottom (clustered), b) Scotch /
Spear thistle across whole site especially on the tops
of western banksides. c) Ragwort in fenced countryside
stewardship.
Area:
Approx. 25 acres.
Conditions:
Moist.
Management
: Controlled & light grazing from 25 head
of cows (+ their followers ?)
Clearing
the weeds (see drawing)
Day
1. Three men pulled docks & Spear thistle in valley
bottom. Ragwort & thistle were pulled from the fenced
countryside-stewardship bank area (to the East). (21 man-hrs)
Day
2. Divided .
Task
A : Three men pulled remaining docks, spear thistle &
ragwort from all over site. Spear thistle was worst (&
distributed from), the top of the Western banksides. (15
man hrs) Cost to walk & clear this field area was
£12 per acre.
Task
B: Two men did a trial hour in the white clover pastures
alongside the road, pulling young docks & spear thistle
(2 man hours). It would take two men a day to clear this
field.
Task
C: One man loaded dock piles into the trailer (1 man hour).
Task
D: Three men cleared Scotch thistle & Docks from the
fence line (between fields of organic wheat & peas.)
Both were left on the ground, docks piled for later collection.
(3 man hours).
Costs:
42 man hours @ £7.14 = £.299.
Expenses £25.
Total:
£324.88p
Assessment:
the mostly deep & moist soil made for reasonably easy
use of the Lazy Dog. A ‘control area to the South of field
‘1’ will show up the work, which needs follow-up (plants
are missed in rough conditions). The follow-up work on
this site should now only be 3 or 4 man hours annually.
The work on the dividing fence was really important, because
it dealt with the source of long term trouble. The trial
hour in the white clover ley suggested that this would
cost no more than £149 to clear.
Important:
It is inevitable that a rosettes & plants will have
been missed (despite thousands cleared). It is essential
to follow up this work by inspecting the fields at a later
stage in the growing season, and by removing plants before
they set seed. Estimate 5 man hours.
[
this report was written by P.Trevelyan 29th April
2003].
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